This Core will provide a tumor/cell line facility which will maintain all of the cell lines to be used and will, in addition, work on improving conditions for growth of tumor cells from human head and neck cancers in vitro and on the establishment of new cell lines from these head and neck cancers. The maintenance of this common tumor cell bank should allow us to standardize results obtained in both the molecular biology and physiology of tumor cells that are exposed to low oxygen conditions. This bank should also minimize intra- and inter-experimental reproducibility with different experimental protocols and will facilitate the exchange of data between researchers. This Core component will serve as a focal point of the Program Project to maintain, propagate, distribute and develop both established human and murine tumor cell lines and establish new tumor cell lines from squamous cell carcinomas of the head and neck. A variety of human tumor cell lines will be used, including human squamous cell carcinoma cell lines A431, A549, HCT-15, HT29 and FaDu, SSC61, SSC35, HNSSC257, SQ20B, JSQ3 derived from head and neck cancers. These cell lines have been selected because they have been well characterized with respect to their hypoxic fraction in tumor xenographs, their response to low oxygen conditions in cell culture cell, survival to ionizing radiation, gene expression, p53 tumor-suppressor gene status, and cell- cycle response to low oxygen conditions. As a major part of this Program Project is to understand the response of human squamous cell carcinomas of the head and neck to low oxygen conditions and bioreductive therapy, we will develop new tumor cell lines from biopsies of these head and neck tumors, either by plating them and establishing cell lines or by passing them into scid-immune deficient mice. The cell line-tumor bank repository portion of the Program Project will be responsible for maintaining the fidelity of the cultures as well as insuring that they are mycoplasma- and bacteria-free. The culture conditions that are maintained in the cell line will be distributed to all users of these cell lines so that they are maintained in similar conditions to facilitate the comparison of data obtained by their usage. All human cell lines that will be developed from biopsies will be tested for the presence of hepatitis and HIV, and will be handled by the guidelines described in the Stanford University Health & Safety protocols.